In recent years, with the virtualization of open systems and servers, management of systems is becoming complicated. Consequently, using storage systems becomes common from the viewpoint of easily managing the systems or flexibly coping with a rapid increase in amount of data.
In the storage systems, disks with different speeds can be used. For example, examples of the disks include solid state disks (SSDs), serial attached small computer system interface hard disk drives (SAS HDDs), serial advanced technology attachment (SATA) HDDs, and the like.
In such a storage system, there may be a case in which several types of disks that have different speeds are used in the storage system and a storage area that is referred to as a single volume is created. Furthermore, for disks with different speeds in a single volume, a technology of tiering storage in an automated way, in which a storage location of data is determined in accordance with the frequency of use has been widely used.
If the technology of tiering storage in an automated way is used, for example, data that is frequently used is stored in a high speed disk in a volume, whereas data that is less frequently used is stored in a low speed disk in the volume. Then, due to automated storage tiering, it is possible to implement high-capacity high-speed storage devices at low cost.
Furthermore, as a technology of adjusting the performance of storage, for example, the band width of a data transfer path between a volume and a server that executes an application is adjusted. This function is sometimes referred to as the Quality of Service (QoS).
Furthermore, as a technology of adjusting the performance of storage, for example, there is a conventional technology of allocating a node such that a service level requirement is satisfied when a task is performed. Furthermore, there is a conventional technology of allocating a pool area to a virtual volume in accordance with a system requirement. Furthermore, there is a conventional technology of customizing a combination of storage devices so as to implement desired performance. Furthermore, there is a conventional technology of changing, on the basis of a system requirement, a logical container that corresponds to the storage destination of data. Furthermore, there is a conventional technology of selecting, from a plurality of pieces of storage/clouds on the basis of the attribute of a file and the attribute of the storage destination, storage/cloud that stores therein a file that satisfies the system requirement.    Patent Document 1: Japanese National Publication of International Patent Application No. 2014-506367    Patent Document 2: Japanese National Publication of International Patent Application No. 2013-536478    Patent Document 3: Japanese Laid-open Patent Publication No. 2014-132457    Patent Document 4: Japanese National Publication of International Patent Application No. 2014-517952    Patent Document 5: Japanese Laid-open Patent Publication No. 2014-10465
However, if the bandwidth is adjusted such that the actual measurement performance matches the target performance, because the actual measurement performance varies due to variation in load, it is difficult to continuously and completely match both the actual measurement performance and the target performance. Accordingly, because adjustment is repeatedly performed such that the target performance matches with the actual measurement performance in accordance with the actual measurement performance, it is difficult to stably operate the system.
Furthermore, with the conventional technology of allocating a node in accordance with a system requirement, because the adjustment of the bandwidth is not considered, it is difficult to implement a stable operation of a system when the bandwidth is adjusted. This also applies to the conventional technologies of allocating a pool area, adjusting a combination of storage devices, changing the placement of a logical container that is the storage destination of data, and selecting storage/cloud.